Wide area network (WAN) standards include, for example, digital subscriber line (DSL), asymmetric digital subscriber line (ADSL), and multiprotocol label switching (MPLS), to mention a few. WANs are used to connect local area networks (LANs) allowing devices in one location to communicate with devices and their users in other locations. In a WAN having a large number of remote sites, connections between the sites are many times statically configured. The dynamics of the network system may also change over time making repeated static configurations of the network inefficient and costly to implement. Further, static connections involve reservations of network resources. As data flow patterns change in the network, the reserved resources create non-optimal static connections which cause the network to reserve bandwidth that could be better used elsewhere in the network.
For example, a site A is anticipated to have high bandwidth requirements for data transfer with site B and site C is anticipated to also have high bandwidth requirements for data transfer with site B. Since at the time the network is configured there may be little anticipated requirement for communication between site A and site C and since sites A and C can communicate to each other by going through site B, a communication path between sites A and C is not statically configured. With the network system operating over time, the original assumptions on communication paths will likely change. For example, sites A and C may require communication at a much higher bandwidth at this later time than is easily achieved by communicating through the intermediate site B thereby causing congestion on the paths between sites A and B and between sites B and C. A reconfiguration of the network is not usually feasible due to configuration overhead and lost time in operating the network. Also, different types of data packets require different types of compression applications to more optimally reduce packet size and improve network use of available bandwidth.
Further, the dynamics of the network system may further change over time making repeated static configuration of the network inefficient and costly to implement. For example, in a ship to shore wireless communication network, the ships are the remote sites and they are in constant motion moving closer and farther from land where their shore communication end points are. The ships distance from shore impacts bandwidth available to the wireless communication system. In addition to the distance, atmospheric conditions also impact the bandwidth and quality of the communications. To preserve the quality of the network, it is best for the users of the network to reduce the amount of traffic being transmitted when conditions cause a reduction of wireless bandwidth. Continuing to send bandwidth at a high rate will simply cause a large number of packets to be lost. When there are multiple wireless links available, users of the network can use other WAN links to supplement the bandwidth lost from a WAN link experiencing a degradation of service. Just as wireless links can degrade due to ship motion and atmospheric conduits, they can also improve due to these changes. Network users should increase their bandwidth usage when wireless conditions improve. This allows traffic to move off of higher-cost links and makes sure that all of the bandwidth that is available can be put to productive use. These wireless networks are much more dynamic than typical wired networks. In a typical wired network, high loss is a symptom of a problem at the service provider, but in wireless environments such disruption is just the nature of the communications medium. In most wired WAN networks, it is possible to statically configure equipment to make use of the WAN and that configuration only needs to be adjusted if the service purchased from the service provider is changed.
As networks become larger and more complex, administrative techniques for managing the network are increasingly more complex and costly. An increasing number of network configurations are configuring high cost links, such as 3G/4G cellular links, in their network as backup links. These high cost backup links either incur significant charges when used or when a monthly data cap is exceeded so the intent is to carry user traffic only when all other links are down. In other words, these backup links are only links of last resort and very costly to use. Users often have a variety of backup WAN links and each of these links have different costs. Some links have a data cap that is covered by a monthly fee, with data usage above that cap incurring significant charges. Other links may incur a significant cost for each byte transmitted. Customers often have a minimum amount of WAN bandwidth that is needed to support critical applications and it is costly if those applications are not available. The most efficient operation of the network often means bringing online a small amount of bandwidth from high cost WAN links to supplement what is available from lower cost WAN links.
It is not always clear how much bandwidth a WAN link can actually support. Service providers may market a WAN service as “Up to X Mbps”, where it is not guaranteed that X Mbps will always be available. To deal with this, users run bandwidth tests that push traffic through the network and measure the capacity. This measurement can be used to configure network equipment that interfaces to the WAN or as a diagnostic aid to support complaints to the service provider if the WAN performance is insufficient. Most of these speed tests use an Internet service to push a large amount of traffic for several seconds. On a production network running business-critical real time applications, this type of network usage can be disruptive. On WAN links that are part of private networks (e.g. MPLS) there may not be connectivity to the Internet service used for the speed test. This speed test can also be time consuming, especially when several WAN links need to be tested. It is desirable to have a testing technique that allows a very small burst of traffic to determine the bandwidth of a WAN link. It is also desirable to run this speed test on private networks.